1. Field of the Invention
The present invention relates to a method for forming a thin film. More particularly, the present invention relates to a method for forming a silicon-containing film and to a method for decreasing the number of particles.
2. Description of the Related Art
Chemical vapor deposition (CVD) is a technology that deposits on a substrate a solid reaction product formed from the reaction of one or more gaseous reactants, and has recently become a major film deposition tool for many conductor, semiconductor and dielectric materials. In semiconductor processes, for example, silicon-containing gases are used frequently for many conductor, semiconductor and dielectric materials contain silicon, wherein silane (SiH4) is used most widely.
However, since a CVD process using SiH4 needs higher temperature and forms a Si-containing film of lower uniformity, SiH4 is not so suitable for deep sub-micron processes that require lower thermal budget and higher uniformity. Hence, in current CVD processes, SiH4 is gradually replaced by disilane or trisilane that decomposes at a lower temperature and is capable of improving the uniformity of the deposited film.
However, since disilane or trisilane decomposes at a lower temperature, it easily causes gas-phase nucleation to form particles. The particles not only contaminate the substrate surface to form defects in the deposited film, but also adhere to the inner surfaces of the reaction chamber to be a contamination source in subsequent uses. The particle problem becomes even more significant in nano-scale fabricating processes.